This method will add a history note for an invoice. We highly recommend that this gets used any time an invoice gets created or altered. It's like a miniature audit trail.
This method will add an invoice line item to the database. It is very important that you get all of the data correct. This is how all of the quantities, sales revenue, tax liabilities, and eventual cost of goods sold are tracked through the system.
This pulls data from the data_change_log table. These are records of edits of customers, parts, purchase orders, invoices and receipts that are only recorded in history.